Hydraulic turbine



WY E um ww C Mm .me wm H sept. e, 1927.

Filed June 17. 192s Patented Sept. 6, 1927.

entre srarss 1,641,353 PATENT OFFICE.

W'ILLIAM `M. "WHITE, Ol IVIELWFAUKEE, XVISCONSIN.

HYDRAULrc TUnBrNn.

Application led June 17, 19.26. Serial No. 116,552'.

This invention relates in general to improvements in the construction and operation of hydraulic machines, and relates mor-e specifically to an improved hydraulic turbine struct-ure embodying a discharge flow decelerator or draft tube.

An object of the invention is to provide an improved hydraulic turbine wherein fiuid which leaks past the joint between the rotor and the casing, may be effectively remover without interfering` with the normal operation or efficiency of the turbine. Another object of the invention is to provide an improved discharge flow dcelerating or draft tube structure for hydraulic turbines or the like. These and other objects of the invention will appear from the :following description.

A clear conception of an embodiment of the invention may be had by referring to the drawing accompanying and forming a part of this specification in which the various parts are designated by suitable reference characters. v

The single figure of the drawing is a fragmentary central vertical section through a hydraulic turbine installation embodying a rotorof the Francis type.

The hydraulic turbine specifically illustrated, comprises in general a Francis rotor 2 secured to the lower end of a vertical main shaft 5 and formed to receive a supply of fluid radially and to discharge? the fiuid therefrom axially of the rotor; a casing comprising upper and lower casing portions 6, 7 cooperating with the rotor 2 to provide annular running joints adjacent to and above and below the inlet portionof the rotor; a fluid supply casing 3 communicating inwardly with the main turbine casing and with the inlet side of the rotor 2 past an annular series of adjustable guide vanes 8; a draft tube 4 having an inlet portion com*- municating with the rotor discharge and having a discharge portion communicating with a tail-race 13; and a foundation 12 constituting` the outer walls of the draft tube 4 and providing a support for the turbine casings 6, 7 and for the supply casing 3. The hub of the roto-r 2 is providedwith` passages 9 extending downwardly therethrough 'rom the space above the rotor. The draft tube 4 is provided with a central core 11 within which is located a pipe 10 the upper end of which communicates with the passages 9 and the lower end of which discharges into a conduit 14 which in turn communicates with the discharge portion of the draft tube in close proximity to the tailrace 13. v

During normal operation of the turbine, fluid is admitted tothe rotor 2 from the supply casing S-past the guide va-nes 4 in a well known manner. The fluid discharged from the rotor 2 is delivered into the upper inlet portion'of the draft tube 4 and advances downwardly through the tube inthe form of a whirling vortex. The velocity of the vortex of'fluid passing through the draft tube 4 is gradually diminished and the de? celerated fiuid is delivered outwardly about and away from the core 11 into the tailrace 13.

The fluid which leaks past the upper joint between the upper portion of the rotor 2 and the upper casing 6 flows downwardly through the passages 9 and into the central pipe 10, from which it is withdrawn through the conduit 14 by the suction within the discharge portion of the draft tube 4. In this manner, the leakage fluid is effectively discharged into a portion of the draft tube 4 wherein its admission will not affect the efficiency of operation of the draft tube. The central core 11 which provides a housing` for the leakage conducting conduitn is also useful in that it provides a filler for the center of the vortex, thereby eliminating eddy currents and other disturbances which might otherwise tend to reduce the efliciency of the draft tube.

` It should be understood that it is not desired to limit the invention to the exact details of construction and operation herein shown and described, for various modifications within the scope of the claims may occur to persons skilled in the art.

t is claimed and desired to secure by Letters Patent:

1. In combination,r a casing, a rotor within and cooperating with said casing to form a running joint, an annular draft tube having` an inlet portion communicating withy said rotor and having a discharge portion communicating with a tail-race, and means disposed centrally of said draft tube for conducting leakage fluid from said joint into said draft tube discharge portion in prox imity to said tail-race.

2. ln combination, a casing, a rotor within and cooperating with said casing to form a running joint, a draft tube comprising an annular outwardly flaring conduit having an inlet portion communicating With said rotor and having a discharge port-ion communicating With a tail-race, and means for conducting leakage fluid from said joint into said discharge portion of said draft tube central ly of said draft tube.

3. In combination, a casi-ng, a rotor Within and cooperating with said casing to form a running joint, a draft tube having a central core vtherein and having a discharge portion communicating with a tail-race remote from said rotor, and means for conducting leakage fluid from said joint through said central core to the discharge portion of said tube in proximity to said tail-race.

4l. In combination, a casing, a rotor Within and cooperating with said casing to form a running joint, the huh of said rotor having passages therein, a draft tube having a cen tral core extending from said rotor hub to a tail-race located remote from said rotor, and conduit means Within said central core for conducting leakage from said rotor passages to the discharge portion of said draft tube in proximity to said tail-race.

5. In combination, a casing, a rotor With in and cooperating With said casing to form a running joint, a drafttube having a hol.- loW central core and a discharge portion communicatingv With a tail-race remote from said rotor, and means for conducting leakage fluid from said joint through the interior of said core to the discharge portion of said draft tube.

6. In combination, a casing, a rotor Within and cooperating with said casing to form a running joint, an annular draft tube having therein a central hollow core the interior of which communicates with the discharge end of said draft tube, and means for conducting leakage fluid from said joint to the interior of said core. Y

In testimony whereof, the signature of the inventor is afliXcd hereto.

WILLIAM M. WHITE. 

